I am a California resident and taxpayer. I don't see this as a tax problem and can't understand how filing as such would change this. I grew up in New York state, where the prison system got a major overhaul after the Attica riots of 1971 and has stayed very clean since. My mother worked in the NYS prisons for 17 years and I never heard anything like this. The big problem is treating the gang members as a group. New York treats prisoners as individuals and does not negotiate with groups. If a prison system of California's size has a problem with gangs, it's not keeping individual members separated sufficiently. Then you don't lock one guy in the hole for years -- you leave him with dudes that don't think he's a leader in a different part of a giant state.
You don't think that part of the problem is that too many people are in prison in the first place? A lot of tax dollars are needed to fund prisons, money that could go toward things that might reduce criminal behavior, like schools and after school programs. Why is it a good idea to gather criminally minded people in a few isolated facilities where their resentment for law can fester and be reinforced as "correct" or improved through the exchange of ideas and the expansion of personal networks of like-minded people?
You may have an interesting long-term question. However the hunger strike needs to be solved right now.